The randomized alphanumeric string ( ynbd56lhwrv0 ) is typical of files generated by cloud storage services (like Google Drive, Dropbox, or WeTransfer) or temporary hosting platforms.

Use a tool like VirusTotal to upload the file (if already downloaded) or the download link to check for malicious code.

Some automated office systems (like network scanners or e-billing software) assign random IDs to PDF files before they are renamed by the user.

Ensure it is a true .pdf . Sometimes malicious files use "double extensions" like ynbd56lhwrv0.pdf.exe to hide their true nature.